IPv4 Subnet Calculator

This calculator and tool allows you to type an IP address in and get information on a particular subnet. Enter an IP or range in CIDR notation.

Network: 4.3.128.0/21
Addresses: 2048 (2¹¹)
First IP: 4.3.128.0 (0.128.3.4.in-addr.arpa)
Last IP: 4.3.135.255 (255.135.3.4.in-addr.arpa)

Owned By: Level 3
/8 Operated By: ARIN

Related Networks

4.0.0.0/8
3.0.0.0/8
5.0.0.0/8
4.3.128.0/20
4.3.128.0/32
4.3.135.255/32

You can also use some of the other examples such as:

0.0.0.0/0
1.0.0.0/8
127.0.0.1
30.0.0.0/8
192.168.0.0/16